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Bad Distributor Symptoms: Things to Look Out For

Distributors are essential parts of a vehicle’s mechanism. In fact, a car won’t run if it has a faulty distributor. The distributor’s primary function includes supporting the engine’s ignition, distributing current, and connecting the spark plugs to the ignition coil.

bad distributor symptoms

Photo Source: http://www.pirate4x4.com/

With that said, bad distributor symptoms can pop out if it is showing signs of wear and tear. Knowing how to spot these signs should be a crucial part of any maintenance work. Today, we’ll discuss where these symptoms come from, how to fix it, and how to prevent it. Stay tuned to find out!

How distributors work

Before anything else, it’s important for you to understand that distributors are mechanical devices that make use of a rotating shaft. With that said, the symptoms that you can expect for this component are all mechanical problems.

The primary mechanism of a distributor is its rotating shaft. Usually, this rotor operates by gears located in the camshaft on overhead valve engines. This rotor is composed of both conductors and insulators. The conductor of the rotor is a metal part that directly makes contact with the ignition coil.

It is a crucial aspect of the rotor since the ignition coil, and the metal conductor is the first passage of electrical current. This transfer is possible through the high voltage cable in the ignition coil.

As this makes contact with the ignition coil, the rotor arm passes near the output wires. These output cables are precisely known as high tension lead wires in the engine. In layman’s terms, you can call this as spark plug wires.

The trick here is that the rotor passes near it, but it does not make contact with it. As the rotor continues to rotate, it creates small gaps for the electrical current to pass. The high tension cables receive this current and immediately transmit it to the spark plug. Once the spark plug ignites, the combustion of the air-fuel mixture can finally begin.

Defective Distributor Symptoms To Look Out For

Now, before you start thinking that your distributor is bad or beginning to wear out, here are some signs you can look out for:

Squealing Noises

Although squealing noises from your car can mean a lot of different things, it can also mean a bad distributor as well. If nothing else seems to be wrong with your vehicle, check the distributor cap.

distributor cap with silicone wires car parts

You might find it dirty, full of pollutant and grease build-up. That causes the high squealing noises as the air circulates through the car engine. However, this does not mean that you have to replace it right away.

You can try solving this by cleaning the distributor cap first. However, if it still doesn’t address the problem, try consulting with a mechanic before replacing the entire distributor.

Difficulties when starting

Another symptom for a bad distributor is a problem when starting. Even more specifically, a problem starting in cold weather or low temperatures. That is because the distributor cap accumulates damages as you initiate the engine in cold weather.

man inspecting car engine in winter

The cold weather also freezes or cools down the cap and the sudden burst of heat when starting the engine causes the distributor cap (usually covered with plastic) to accumulate cracks and eventually break.

However, you can avoid this situation altogether by keeping your vehicle from extreme weather or temperatures. Having your garage with a heater for cold seasons is highly ideal.

Vibrations or shaking

The third symptom to look out for would be excessive vibrations or shake. It is usual to experience shaking when starting the engine or when shifting gears (especially for manual transmission).

However, unreasonable shaking while the car is running is a sign that something is wrong with your distributor. What is even more alarming would be stronger vibrations that you can feel throughout the vehicle.

That can be because of the distributor not spinning properly or just a faulty distributor cap. Either way, these two aren’t problems to be ignored.

Related: Why My Car Jerks When Accelerating?

Distributor cap cracks

The distributor cap is an essential part of the device simply because it is its primary protection. An engine is a place where a lot of mechanical energy generates heat. The heating happens due to friction. Thus, this friction can hurt unprotected components like the rotor of the distributor.

automotive ignition tune up parts over white

When this happens to your distributor cap, replacement is the best option. Patching it up through remedies will only be a quick solution. In fact, it might even worsen the problem in the long term. That is why it’s always best to spend a little more when it comes to exterior damages.

Inconsistent RPMS

Fifth would be incompatible RPM or revolutions per minute. If your RPMS seems to be off, then it might be best to check the distributor. This symptom is usually a sign that your distributor wires (the connection between the cap) have already gone defective.

Or again, the distributor cap can be burned, corroded or damaged. You can start resolving this by testing each of the wires.

Read more: http://forums.turbobricks.com/showthread.php?t=289701


You might have expected this a bit sooner on the list. After all, this might be the most prominent symptom of a faulty distributor. Earlier, we explained that the device is responsible for routing high voltages from the ignition coil down to the spark plugs.

A part of this responsibility is to also transmit the current in the correct time and correct firing order. A distributor that does this is what makes it completely functional without any flaws.

Since backfiring happens mostly due to incorrect firing order, this can be rooted to your distributor. However, it’s important that backfiring is a broad problem. Thus, an engine that’s backfiring can have different causes. One of the most prominent ones includes retarded timing of the valves and low fuel pressure.

Wrapping it Up

Distributors are something you can’t overlook. It’s an integral part of the engine’s overall mechanism, and it won’t operate properly without it. A bad distributor is worse than a bad oil filter, or a faulty radiator. It’s a direct component to your car’s fuel combustion.

Thus, it’s always important to be ready and to be aware. There’s no other way to prevent this other than responsible maintenance. Distributors are easy to check because it’s not deep down the engine assembly. A few rundowns on the distributor cap, the rotor, and the placement of the ignition coils should do the trick.

Should the damage be done, then you’re always left with different choices and strategies to go about it. Distributors are not that hard to work on, so take the extra mile to fix it yourself! Good luck!

Steven K. Galloway